The invention relates to a high-voltage circuit-breaker with dual motion of the contacts and incorporating an insulating gas puffer system with a semi-moving piston and optionally a closure resistance inserter.
High-voltage circuit-breakers with dual motion of the contacts are known in the art, and one example is described in the document FR-A-2 737 937 in particular. A high break capacity can be obtained with those circuit-breakers because the dual-motion feature means that their contacts move in opposite directions, which leads to fast separation of the contacts when the circuit-breaker opens.
An insulative gas puffer system is provided for fast extinction of the electrical arc that is formed between the arcing contacts if they separate when the circuit-breaker is live. The insulative gas used to extinguish the arc is conventionally compressed by a piston, and this compression operation cannot be instantaneous. It is therefore difficult to obtain optimum compression with prior art dual-motion circuit-breakers, because the movement of the compressor piston in those devices is mechanically linked to the faster movements of the circuit-breaker contacts. The resulting solutions are therefore unsatisfactory.
For example, opening the contacts of a circuit-breaker by moving the compression piston and the moving contact assembly of the circuit-breaker in opposite directions to accelerate the compression of the insulating gas for blowing out the arc when the circuit-breaker opens is known in the art.
However, such movement causes stresses and forces which compromise good operation of the compression chamber.
Another consequence of this is that the duration of closure resistance insertion is too short for a circuit-breaker in a long high-voltage network and having poles in which the symmetrical dual motion is obtained by a rack system, if a resistance inserter device in series with the contacts is associated with each pole to limit the surges that occur on closing the circuit-breaker.
The invention therefore proposes a dual-motion multipole circuit-breaker in which the speed of the compressor piston and the speeds of each of the moving and semi-moving contact assemblies are different. Each pole of the circuit-breaker includes a case defining a break chamber designed to be filled with dielectric gas and containing a fixed assembly including two aligned conductive tubes on respective opposite sides of a central area provided for the pole contacts and each connected to a different external connection terminal, said contacts being divided between two complementary moving contact assemblies moving in translation along a common axis XXxe2x80x2 and interconnected successively by two coaxial annular contacts, namely a wear contact and a permanent contact. One of the two assemblies constitutes a semi-moving assembly and has a permanent contact member consisting of the outside wall of a first cylindrical conductive member adapted to slide inside the annular permanent contact member of the other assembly, referred to as the moving assembly, and in one of the fixed tubes to which that member is electrically connected, via its wall. The annular permanent member of the moving assembly is carried by another cylindrical conductive member adapted to slide in the other fixed tube to which that other member is electrically connected, as well as a wear contact member consisting of a conductive termination mounted at the end of a conductive support rod fixed axially inside said other conductive member. The rod is adapted to penetrate axially into an arc blast nozzle, which it then blocks and which defines an arc expansion volume around a wear contact member complementary to the conductive termination and carried axially by the first conductive member of the semi-moving assembly, as well as the nozzle which is fixed to the end of that first member at the border of the volume. The latter is adapted to be filled with gas through a wall which separates it from a compression chamber formed in the first conductive member between that wall and a compressor piston moved with the two assemblies.
According to a feature of the invention, the circuit-breaker includes a drive rod disposed axially in the pole including it and movable in translation between a fully inserted position in which the contacts of the assemblies are interconnected and a fully open position in which the contacts are separated. The drive rod carries the first member of the semi-moving contact assembly that it drives when it moves and co-operates with a first linkage through which said other member of the moving assembly is driven. The linkage is adapted, when the drive rod is pulled from its fully inserted position, to cause in succession an initial displacement of the two assemblies in the same direction as the rod, followed by movement of the moving assembly in the opposite direction to the semi-moving assembly, after said moving assembly has stopped and until the drive rod reaches its open position, after separation of the contacts. The drive rod co-operates with a second linkage which drives the compressor piston in the opposite direction relative to said first member, on which it slides, until the contacts are separated.
According to a feature of the invention, the first linkage is adapted to move the two assemblies at the same speed in opposite directions when the contacts are separated.
According to a feature of the invention, the first linkage includes:
a first shaft mounted transversely on the drive rod near the actuator end of that rod,
a second shaft mounted transversely on the tube through which the rod passes, the rod incorporating a longitudinal opening through which the shaft passes,
a system including at least one relatively long shaft actuator link and one relatively short shaft actuator link which are articulated and connect the first and second shafts so that any movement of the rod causes corresponding rotation of the second shaft, and
a system including at least one relatively short moving assembly drive link and one relatively long link connecting the second shaft to a shaft fastened to said other conductive member which carries the moving assembly to move it as indicated.
According to a feature of the invention, the relatively long and relatively short shaft actuator and moving assembly drive links are provided in pairs and form two sub-assemblies on respective opposite sides of the drive rod.
According to a feature of the invention, a relatively long shaft actuator link is cranked where it bears against the second shaft in the fully inserted position of the drive rod in which the contacts are interconnected and in which a relatively short moving assembly drive link is at an obtuse angle to the corresponding relatively short shaft actuator link at the second shaft to which they are fixed, so that the two shafts carried by each of them are on the same side of the drive rod when the drive rod is in the fully inserted position and the relatively short shaft actuator link extends beyond the rod after limited displacement of the drive rod from the fully inserted position.
According to a feature of the invention, the second linkage includes:
a drive shaft mounted transversely on the drive rod, and
a system including at least one relatively long compression link and two relatively short compression links articulated to a common shaft, said relatively long compression link being also articulated centrally to the compressor piston and the relatively short compression links being respectively articulated to the drive shaft and to a fixed shaft.
According to a feature of the invention, the circuit-breaker includes a pair of relatively long compression links and two pairs of relatively short compression links which form two sub-assemblies on respective opposite sides of the tube containing the drive rod.